Gaskets have been made from a variety of structural materials, including polymers such as ethylene/vinyl acetate (EVA) and polyvinyl chloride (PVC). For example, U.S. Pat. No. 4,984,703 discloses plastic closures which have a sealing liner comprising a blend of ethylene/vinyl acetate and a thermoplastic elastomeric composition.
Depending on the use environment, gaskets can have varying degrees of properties. For example, in corrosive service conditions, the gasket should be impervious to the material in question, but still resilient enough to form a seal. Gaskets used in the food and beverage area have similar requirements, but cannot contaminate the foodstuff. For example, when a gasket is used as a bottle cap closure liner and the closure is applied and removed (and/or resealed), it is desirable for the gasket to retain its integrity and not shred or tear (known in the industry as “stringing” or “scuffing”) such that pieces of it contaminate the foodstuff. Further, the gasket or closure liner should not deform such that it loses its seal integrity. Depending upon the type of food and/or liquid contents, the filling temperature might be lower or higher than room temperature, thus placing even greater demands on the gasket.
While there have been many different gasket materials, there continues to exist a need for olefin polymers and olefin polymer compositions useful in making gasket materials, and in the case of foodstuff, without adversely contributing to the taste and/or odor of the product.